Democratic primary candidate for mayor of New York City Christine Quinn reacts during the first debate at Town Hall. / Pool, Getty Images

by Martha T. Moore and Kevin Johnson, USA TODAY

by Martha T. Moore and Kevin Johnson, USA TODAY

NEW YORK â?? Two decades after crime began to plunge in New York, five Democrats running for mayor are competing to rein in ''stop and frisk,'' a law enforcement strategy that police say is a cornerstone of the decline.

Taking their cue from a federal court decision two weeks ago that found the street stop program racially discriminatory, candidates are striving to contrast their opposition to stop-and-frisk with Mayor Michael Bloomberg's fierce support.

The Democratic candidates, who will compete in a primary Sept. 10, are following on a court decision Aug. 13 that declared "stop-and-frisk'' to be racially discriminatory. Last year, police stopped more than 500,000 people, of whom 87% were black or Hispanic, according to data compiled from police reports by the New York Civil Liberties Union. Fewer than 10% of the minorities stopped by police were arrested.

"Too many men of color are being stopped in the streets of New York,'' Christine Quinn, who is battling Public Advocate Bill de Blasio for the top spot in opinion polls, said this week. "As mayor I'll ensure that unconstitutional stops end.''

The candidates' criticism of stop-and-frisk comes alongside a federal court ruling Aug. 13 that found the stops to be racially discriminatory and ordered a federal monitor. The Bloomberg administration has appealed the decision. But Democratic mayoral candidates have unveiled their own plans to restrict the practice.

John Liu, city comptroller also running for the top job, says he would end stop-and-frisk entirely. Former representative Anthony Weiner proposes police wear lapel cameras to record street stops - also called for by the federal court decision. Bill Thompson, former comptroller and the only African-American candidate in the race, said that stop-and-frisk creates "institutionalized suspicion'' of minorities. "It is a policy that has been misused and abused,'' he said recently on MSNBC. He wants police to issue tickets explaining the reason for the stop.

On Thursday, the city council, of which Quinn is speaker, voted to appoint an outside watchdog for the police department to monitor stop-and-frisk. A second bill - which de Blasio supported but Quinn did not - allows residents to sue in state court over racial profiling in police stops. Both measures overrode vetoes by Bloomberg. Police Commissioner Ray Kelly said Thursday the legislation is "unwise and will undermine public safety.''

All the Democratic candidates but Quinn have said they would replace Kelly, who has been mentioned as a possible Homeland Security chief by President Obama.

Street stops date to the Rudy Giuliani administration, but the number has soared under Bloomberg, from 97,296 in 2002 to a peak of 685,724 in 2011, according to police data analyzed by the New York Civil Liberties Union.

Police credited stop-and-frisk with removing thousands of illegal guns from the streets. In 1990, 2,262 people were murdered in the city, according to police data. Last year the total was 417. New York's anti-crime tactics, including stop-and-frisk, have been widely copied by other police departments across the country.

Some analysts view the political debate in New York on the controversial stop-and-frisk tactic as an extension of the national movement toward less extreme criminal justice policies implemented at a time when crime was surging.

Earlier this month, Attorney General Eric Holder called for an end to mandatory minimum prison sentences for non-violent drug offenders who have been crowding the federal prison system.

The proposal follows legislative or administrative action in more than a dozen other states in recent years - mostly driven by the rising costs of incarceration - to enact differing approaches to crime, emphasizing treatment and other alternatives to incarceration.

The dramatic downturn in crime has provided time for analysis about "what works and doesn't work'' in law enforcement, says William Bratton, New York police commissioner under Giuliani and also former top cop in Los Angeles. With that luxury, "we're peeling back the layers on the crime problem,'' he said. "The lock 'em up philosophies of the 1980s and '90s had unintended consequences that we are now trying to correct.''

The historic low crime rate has also brought questions about the tactics' fairness as well as efficacy.

"Without the great drop in crime in the past 20 years, I doubt you would see the kind of political and public support that now exists for altering stop-and-frisk and other strategies,'' said University of Pittsburgh law professor David Harris, who specializes in criminal justice and police issues. "If people still felt a great deal of fear, the current public and political mood would likely be entirely different.''

Implementing a federal monitor and an inspector general will hobble police effectiveness, says Heather MacDonald of the Manhattan Institute, a conservative think tank, who believes the court decision was unjustified. "People have forgotten what the city was like, and there are a lot of new residents who weren't here when we had over 2,200 homicides a year and children were sleeping in bathtubs.''

The aggressiveness with which candidates are taking on the police represents a sharp turn away from Bloomberg's adamant support of police strategy, including, for instance, the arrests of thousands of protesters during the 2004 Republican convention, almost all of which were thrown out of court.

More than a decade after the Sept. 11 terrorist attacks brought an intense and highly visible level of police presence to the city streets, voters are "less willing to take politicians' word for how to effectively and appropriately pursue security issues now,'' says Costas Panagopoulos, director of the elections and campaign management program at Fordham University. "There's far greater scrutiny.''

Bratton said the politically charged rhetoric has merely served to mischaracterize stop-and-frisk, which he called "essential to American policing.''

"If there were not a mayoral election, it (stop-and-frisk) would not be resonating as it is now,'' Bratton said. "The (strategy) was not ruled unconstitutional, it was the way it was being applied. I'm not sure that was understood."

He called street stops an "essential'' police tool, as long as it is applied consistently. "You can't police differently in white neighborhoods than you do in minority neighborhoods.''